On cost‐based routing in connection‐oriented high‐speed networks

Abstract

Not only does cost‐based routing achieve a higher throughput, it also removes the instability problem inherent in fixed‐path routing networks with alternate paths. In the paper we evaluate the performance of two cost‐based routing schemes: one centralized and one distributed. The latter has a much lower complexity than the former. Although the distributed version does not always use the least‐cost path, our results indicate the performance of both schemes are about the same. We also compare them with least‐loaded routing to demonstrate the ability of cost‐based routing to stabilize the network performance even under an over‐loaded condition.

But to make cost‐based routing a viable option for a high‐speed network, we must find a way to compute the cost function. Recently a theory based on the concept of quantization was developed. It can significantly reduce the complexity of cost computation. With this problem solved, cost‐based routing becomes a serious contending routing algorithm for a high‐speed multirate network. The results in the paper demonstrate that the performance degradation caused by quantizing the cost function is insignificant.